Thickeners serve to increase the viscosity of flowable compositions.
Thickeners that are customary, in particular, in cosmetics are, for example, high molecular weight polyacrylic acids (INCI name: Carbomer), which are used in their neutralized form as water-soluble thickeners.
Associative thickeners is the term used to refer to polymers which, although they are rendered water-soluble with ionic groups such as carboxyl groups, have a thickening effect which is not based on their high molecular weight, but on the fact that the longchain aliphatic side groups incorporated in small amounts into the polymers associate.
These polymers can be prepared, for example, as solution polymers or emulsion polymers and be used starting from this form. Polymers of this type are described, for example, in DE 3404537 and EP 11806 (Dow Chemicals).
Although most of the polymers known as thickeners have very good thickening properties, they also have disadvantages, when further requirements are placed on them apart from the thickening effect.
It is often desired, particularly in cosmetics, that polymers simultaneously satisfy a plurality of tasks, for example in addition to the thickening property, also have film forming properties.
The film-formation in hair cosmetics serves primarily to set the hair or to be able to better shape it.
Although known emulsion polymers, which are often based on ethyl acrylate, are good film formers, they are often too sticky and therefore also do not have satisfactory setting properties. The films formed by them are too soft and do not impart any additional performance to the hair.